Where can I find a four pin to three pin adaptor?

[calstar]

Just got a little camper and the running lights have a three pin connector. Do I need an adaptor or can I just plug the three pin into the four pin that goes to my trailer using a splitter? I've googled searched but no luck,
Here's what I have:

thanks, Brian

 

[billy2]

TAG. I have the same thing on my new rig and would like to know.

 

[calstar]

I ended up just using a 4 pin but using only the ground and two hots on it. The yellow on mine is interior camper circuit(only a couple of lights, very small camper), the green is the running lights circuit. Hope this make sense, I can post a pic, there are two unused pins on the 4 pin, looks a little odd but not an issue for me.

Brian

 

[Doc Foster]

Try etrailer
http://www.etrailer.com/dept-pg-Wiring-sf-Wiring_Adapters.aspx